Mine prop



May 9, 1939- F. M. WITTMAN ET AL. 2,158,018

MINE PROP Filed April so, 1957 @@MAJM 4m mmm s Patented May 9, 1939 PATENT OFFICE lVIlNE PROP Frederick M. Wittman, Fairmont, and Harry H. Parrack, Barrackville, W. Va.

Application April 30, 1937, Serial No. 140,014

1 Claim.

This invention relates to certain new and useful improvements in mine props, the object being to provide a mine prop with an attachment by means of which the length of the same can be increased or decreased at the will of the user whereby the mine prop can be used over and over again.

Another object of our invention is to provide a mine prop which comprises a cap adapted to be embedded in the end of a wooden post carrying a screw provided with a head.

A still further object of the invention is to provide a mine prop with a detachable member which can be readily attached or detached therefrom,

the same being held in position on the end of the post by having members embedded within the post, said members preventing the cap from rotating and preventing the post from splitting.

Other and further objects and advantages of the invention will be hereinafter set forth and the novel features thereof defined by the appended claim.

In the drawing,

Figure 1 is a side elevation of a mine prop constructed in accordance with our invention showing the post in section and broken away;

Figure 2 is an enlarged vertical section through the upper portion of the prop; and

Figure 3 is an inverted view of the cap showing the spurs carried thereby.

In carrying out our invention we employ a wooden post I of any size desired which is provided with a longitudinally disposed bore 2. Disposed on the end of the post is a cap 3 which is provided with a marginal annular depending flange 4, the inner wall of which is beveled as shown at 5 to provide a knife edge so that when pressure is applied to the same, it will embed itself in the end of the post as clearly shown in Figures 1 and 2.

The cap 3 is provided with spaced threaded bores 6 in which are threaded the threaded shanks 1 of spurs 8 which are adapted to embed themselves in the end of the post to prevent the cap from rotating. The cap is provided with a threaded bore 9 disposed in alignment with the bore 2 formed in the post and mounted within the threaded bore 9 of the cap is a screw I0 which is provided with an annular flange Il adjacent its upper end having a transverse bore I2 into which is adapted to be placed a pick or other suitable implement for rotating the screw within the bore of the cap in order to raise the same up 5 and down in order to allow it to adjust itself.

The screw has an unthreaded end I3 which is: revolubly mounted in a bore I4 of a head I 5 and is secured therein by swedging the same as shown at I6, the head resting on the annular ange II 10 and is supported thereby so that it can rotate independent of the screw and the screw can rotate independent of the head.

The head is provided with upwardly extending flanges II forming between the flanges means for 15 receiving a support (not shown) which will prevent the head from turning after being in position when the screw is rotated.

This provi-des an exceedingly simple and cheap construction of mine prop wherein an ordinary 20 wooden post is employed and carries an adjustable head whereby the length of the prop can be increased or decreased by simply rotating the screw within the cap.

From the foregoing description it will be seen 25 that we have provided a mine prop in which a cap is secured to the end thereof by having the flange embedded within the end of the post which prevents the post from splitting and by having the spurs, the cap is prevented from rotating so that 30 the screw can be revolved in order to adjust the head in respect to the end of the post.

What we claim is:

In a mine prop, the combination with a wooden post provided with a longitudinally disposed bore 35 at one end thereof, of a cap having a marginal annular depending flange provided with a knife edge adapted to be embedded in the end of said post around said bore for preventing the post from splitting, said cap having depending spurs within 4o said flange adapted to be embedded within the end of said post for preventing the cap from rotating in respect to the post, said cap having an internally threaded bore, a screw working in said bore and a head swiveled on the end of said screw.

FREDERICK M. WITTMAN. HARRY H. PARRACK. 

